If you are cooking beans, wash it well and soak it for at least 30 minutes in clean water before cooking it. As per my experience, I use pressure cooker to tenderize red kidney beans for cooking chili beans. It takes 20 minutes for the pressure cooker to do its job. But after soaking in water before cooking, it only takes half the time for the pressure cooker to tenderize the beans. Think of the savings on gas or electricity.